public class angle extends shape1{
    double a,b,c,s;
    angle(double a,double b,double c){
    	this.a=a;
    	this.b=b;
    	this.c=c;
    }
	public double getArea() {
		s=(a+b+c)/2;
		return Math.sqrt(s*(s-a)*(s-b)*(s-c));
	}
	public double getperimter() {
		return a+b+c;
	}
}
